Landforms and structure

Most of the major units of the earth’s surface owe a great deal to uplift of land over very extensive areas, achieved in many different ways during Tertiary times. The configuration of the broader relief features, like mountain ranges and plateaux, reflects the differences in folding and faulting, and the spatial relationships of broad areas of rocks of differing resistances produced by these recent geological events. Viewed from all angles, landforms almost invariably reflect in some degree the differing resistances to erosion of the underlying rocks. In cross-section a relatively resistant rock may occupy low ground simply because it is low in a horizontal or gently dipping stratigraphical sequence, but there are often reasons for inferring that higher areas owe their altitude to greater resistance of the rocks to weathering, particularly in areas of older or unstratified rocks.